Electrostatic Spray Nozzle with Embedded Charging Electrode
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Solution Overview
Problem
Existing electrostatic spray systems face challenges in achieving effective atomization and charging of sprays using highly conductive liquids, particularly due to high pressure requirements for air compression, which leads to costly, heavy, and energy-intensive equipment, and exposes operators to hazards from exposed electrodes and leakage currents.
Innovation Solution
A portable electrostatic spray system with a nozzle assembly featuring an embedded electrostatic charging electrode and insulating standoffs, coupled with a low-pressure air turbine for atomization, and a tethering system that includes a liquid supply, air supply, and power lines to maintain consistent charging and reduce operator exposure to electrical hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure compressed air (14.5 to 46 psi) is used to atomize spray and keep electrodes clean, then proper atomization and electrode protection are achieved, but the equipment becomes costly, heavy, and energy intensive
Solution Approach 1:
The patent replaces the mechanical compression system (positive displacement compressors) with a turbine-based air generator that produces lower pressure air (less than 14.5 psi). This substitution reduces the weight, cost, and energy consumption of the air generation system while still achieving proper spray atomization through the turbine's rotational energy.
2Quantity of substance
If exposed exterior electrodes are placed near the spray exit for induction charging, then droplet charge-to-mass levels are improved, but operator safety is compromised due to electrical hazards
Solution Approach 1:
The patent extracts the electrode from the exposed exterior position and relocates it to an embedded position within the nozzle body. This extraction from the hazardous external environment maintains the electrostatic charging function while eliminating direct operator exposure to high voltage components and leakage currents.
Solution Approach 2:
The electrode is nested within the nozzle structure, specifically embedded in the nozzle body surrounded by insulating material. This nesting configuration protects the electrode while maintaining its proximity to the spray for effective induction charging.
3Quantity of substance
If exposed electrodes are used for electrostatic charging, then spray charging is effective, but leakage current increases and spray charge reduces when electrodes are wetted by liquid spray
Solution Approach 1:
The electrode is nested within the nozzle body and surrounded by insulating material that prevents liquid spray from contacting the electrode. This protective nesting maintains the electrode's charging effectiveness while preventing wetting that would cause leakage current and charge reduction.
Solution Approach 2:
An insulating barrier (intermediary material) is introduced between the electrode and the liquid spray. This intermediary prevents direct contact between the conductive liquid and the electrode, eliminating the leakage current path while allowing the electrode to maintain its charging function through induction.
4Weight of moving object
If lower pressure air is used to reduce equipment costs and weight, then equipment becomes more portable and affordable, but spray atomization and electrode protection become insufficient
Solution Approach 1:
The patent substitutes the high-pressure mechanical compression system with a turbine-based air generation system that produces lower pressure air. This substitution reduces equipment weight and cost while the turbine's rotational energy provides sufficient atomization capability without requiring high pressure.
Solution Approach 2:
The insulating barrier acts as an intermediary that protects the electrode from liquid wetting even at lower air pressures. This intermediary ensures reliable electrode protection and consistent charging performance regardless of the reduced air pressure environment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves consistent and efficient electrostatic charging and atomization with lower pressure air, reducing equipment costs and operator risk, while maintaining effective spray distribution and deposition on complex surfaces.
Implementation Method 1
an electrostatic charging electrode electrically coupled to receive the electrostatic charging voltage and configured to inductively charge the atomized spray
Implementation Method 2
They also utilize air shear forces to atomize the spray rather than atomization by hydraulic pressure
Data Source
AI summary
A spray system includes a spray device with a housing enclosing an electrostatic power supply that generates an electrostatic charging voltage and a nozzle assembly including a liquid tip that receives a spray liquid and an air stream and emits an atomized spray and an electrode coupled to receive the electrostatic charging voltage and configured to inductively charge the spray. A base unit includes a liquid source that supplies the spray liquid, an air source that supplies the air stream and a power source that supplies power for the electrostatic power supply. A tether couples the spray device to the base unit. The tether includes a liquid supply line coupling the liquid source to the liquid tip, an air supply line coupling the air source to the liquid tip, and a power supply line coupling the power source to the electrostatic power supply.